This invention relates to an abnormality detecting apparatus for a driving system of an automotive generator-motor device which is operable as a power generator or an electric motor.
Recently, there is a trend for an automotive generator usable as an electric motor so that the automotive generator can perform a power generating action as well as an electric motor action. For example, the automotive generator possessing the motor function can serve as a starter for an engine or an assistant power source for an engine available in a high-speed or severe driving condition. Especially, when this kind of generator-motor device selectively acting as a power generator or an electric more is used to start the engine or a vehicle, it is mandatorily required to generate a large starting torque as an electric motor and is also required to generate a large power output as a power generator.
The generator-motor device is generally connected to an engine via an endless driving belt entrained between pulleys attached their output/input shafts. A tension acting on this belt varies widely and causes the belt to undesirably or excessively stretch or wear. The excessively stretched driving belt may cause a slip. No driving force will be transmitted between the engine and the generator-motor device. The generator-motor device may suddenly stop its power generating action or electric motor action even when a vehicle is running on a road.
For the purpose of reducing the emission of harmful substances contained in exhaust gas or to improve the fuel economy, many of the vehicle drivers try to stop the rotation of the engine while they are forced to wait for the traffic signal turning into green (indicting a xe2x80x9cgoxe2x80x9d sign) at a crossing or at an intersection. This is generally referred to as idling stop. To this end, the drivers frequently repeat startup and stop operations of the engine. Therefore, the driving belt entrained between the generator-motor device and the engine is subjected to large and frequent changes of the tension acting thereon. This induces excessive stretch and wear of the belt.
If the electric motor action is no longer feasible for the generator-motor device, it will be difficult to restart the engine of a vehicle which may be stopped at a crossing or at an intersection. If the power generating action is no longer feasible for the generator-motor device, it will be difficult to charge the battery and the engine will not be driven.
To avoid such emergent situations, it is desirable to promptly detect any abnormality of the driving belt, including excessive stretch and wear, before the belt loses its essential functions.
In view of the above-described problems, the present invention has an object to provide an abnormality detecting apparatus for a driving system of an automotive generator-motor device which is capable of promptly and accurately detecting excessive stretch or wear of a driving belt entrained between an engine and the generator-motor device.
In order to accomplish the above and other related objects, the present invention provides a first abnormality detecting apparatus for a driving system of an automotive generator-motor device which is connected to an automotive engine via a driving belt and is selectively operable as a power generator or an electric motor, characterized by the following features. A first rotational speed detecting means is provided for detecting a rotational speed of the automotive engine. A second rotational speed detecting means is provided for detecting a rotational speed of the generator-motor device based on an induced voltage of any one phase of a multiphase armature winding equipped in the generator-motor device. A rotational speed difference detecting means is provided for detecting a difference between the rotational speed detected by the first rotational speed detecting means and the rotational speed detected by the second rotational speed detecting means. And, a warning means is provided for giving a warning or alarm when a rotational speed difference detected by the rotational speed difference detecting means exceeds a predetermined value.
The driving belt connecting the engine and the generator-motor device causes a slip before it is fatally damaged. Under such a slipping condition, the driving belt cannot accurately transmit the rotation of the engine or the generator-motor device to the other. Similarly, an excessively stretched driving belt will cause a significant time lag in the transmission of a driving force between the engine and the generator-motor device.
The first abnormality detecting apparatus of the present invention steadily monitors the occurrence of such emergent conditions of the driving belt during the power generating action or during the electric motor action based on a difference between the rotational speed of the engine and the rotational speed of the generator-motor device. Then, the first abnormality detecting apparatus generates or gives a warning or alarm in advance before the driving belt loses its essential functions, thereby letting each vehicle driver know the abnormality, such as excessive stretch or wear, having been occurring on the driving belt. Hence, the vehicle driver can repair the worn or damaged driving belt at an early stage. Especially, the first abnormality detecting apparatus detects the rotational speed of the generator-motor device based on the induced voltage of any one phase of the multiphase armature winding equipped in the generator-motor device. This is advantageous in that the rotational speed detection of the generator-motor device can be accurately performed without requiring a hall device of any other expensive rotational speed sensor.
Furthermore, the present invention provides a second abnormality detecting apparatus for a driving system of an automotive generator-motor device which is connected to an automotive engine via a driving belt and is selectively operable as a power generator or an electric motor, characterized by the following features. A first rotational speed detecting means is provided for detecting a rotational speed of the automotive engine. A second rotational speed detecting means is provided for detecting a rotational speed of the generator-motor device based on a voltage appearing at a neutral point of a Y-connected multiphase armature winding equipped in the generator-motor device. A rotational speed difference detecting means is provided for detecting a difference between the rotational speed detected by the first rotational speed detecting means and the rotational speed detected by the second rotational speed detecting means. And, a warning means is provided for giving a warning or alarm when a rotational speed difference detected by the rotational speed difference detecting means exceeds a predetermined value.
According to the second abnormality detecting apparatus of the present invention, the rotational speed of the generator-motor device is detected based on the voltage appearing at the neutral point of the Y-connected multiphase armature winding equipped in the generator-motor device. This is also advantageous in that the rotational speed detection of the generator-motor device can be accurately performed without requiring a hall device of any other expensive rotational speed sensor. Therefore, the vehicle driver can know the abnormality of the driving belt, such as excessive stretch or wear, at an early stage. Furthermore, the voltage change at the neutral point reflects any abnormality caused in the multiphase armature winding. Thus, it becomes possible to generate or give a warning or alarm based on a different kind of abnormality. As a result, the second abnormality detecting apparatus makes it possible to prevent power generation failure induced by an abnormality of the multiphase armature winding as well as engine startup failure induced by this power generation failure.
Furthermore, the present invention provides a third abnormality detecting apparatus for a driving system of an automotive generator-motor device which is connected to an automotive engine via a driving belt and is selectively operable as a power generator or an electric motor, characterized by the following features. A first angular acceleration detecting means is provided for detecting an angular acceleration of the automotive engine. A second angular acceleration detecting means is provided for detecting an angular acceleration of the generator-motor device. An angular acceleration difference detecting means is provided for detecting a difference between the angular acceleration detected by the first angular acceleration detecting means and the angular acceleration detected by the second angular acceleration detecting means. And, a warning means is provided for giving a warning or alarm when an angular acceleration difference detected by the angular acceleration difference detecting means exceeds a predetermined value.
The third abnormality detecting apparatus of the present invention steadily monitors the occurrence of emergent conditions of the driving belt during the power generating action or during the electric motor action based on a difference between the angular acceleration of the engine and the angular acceleration of the generator-motor device. Thus, the vehicle driver can know the abnormality of the driving belt, such as excessive stretch or wear, at an early stage. Furthermore, the third abnormality detecting apparatus is advantageous in that instantaneous and responsive abnormality of the driving belt can be detected adequately. Thus, the third abnormality detecting apparatus makes it possible to promptly and accurately detect any abnormality in the driving system.
Preferably, the second angular acceleration detecting means detects the angular acceleration of the generator-motor device based on an induced voltage of any one phase of a multiphase armature winding equipped in the generator-motor device. This is advantageous in that the angular acceleration detection of the generator-motor device can be accurately performed without requiring an expensive angular acceleration sensor.
Preferably, the second angular acceleration detecting means detects the angular acceleration of the generator-motor device based on a voltage appearing at a neutral point of a Y-connected multiphase armature winding equipped in the generator-motor device. This is also advantageous in that the angular acceleration detection of the generator-motor device can be accurately performed without requiring an expensive angular acceleration sensor. Furthermore, it becomes possible to detect any power generation failure induced by an abnormality of the multiphase armature winding.